A commutator for a brushed electric motor typically includes a commutator body made of electrically insulating material, a plurality of commutator segments circumferentially spaced on the commutator body for making slide contact with the brushes of the motor, and a plurality of conductive terminals integrally extending from corresponding commutator segments.
In a known method of forming the commutator, the commutator body and the commutator segments are formed separately and the commutator segments are assembled on the outer surface of the commutator body. In another known method, an axially extending metal ring, with conductive terminals extending from one end thereof and a plurality of anchors formed on an inner surface, is firstly provided. The commutator body is then molded to the inner side of the metal ring such that the commutator body is fixed to the inner surface of the metal ring with the anchors embedded in the commutator body. Finally, a plurality of axially extending through slots are formed in the metal ring at positions between adjacent conductive terminals such that commutator segments electrically insulated from each other by the through slots are formed.
Both the assembled method and the molded method can make satisfactory commutators, the fixing of the segments to the base require the commutator base to be of a certain minimum size which is restricting the miniaturization of very small commutator motors.
The present invention aims to provide a new commutator that can be made with a reduced size, which makes it possible to produce a smaller electric motor.